Fully selective intramolecular ortho photocycloaddition of 4-(4-methoxy-phenoxy)-3-(N3-benzoylthymin-1-yl)but-1- ene: an unprecedented benzene–thymine photocycloaddition

Abstract

On irradiation of 4-(4-methoxyphenoxy)-3-(N ³ -benzoylthymin-1-yl)but-1-e ne 1 at 254 nm in THF a single photoadduct 2 is formed as a result of chemo-, regio- and stereo-selective intramolecular ortho photocycloaddition of the thymine double bond to the 1,2-positions of the phenyl ring.